1. Field of the Invention
The invention is based on an accelerator pedal module in particular for use in control of an engine.
2. Description of the Prior Art
Japanese patent application no. 60-99729 (JP-A-60-99729) has disclosed an accelerator pedal module with a pedal lever pivotably supported on a support structure, with a sensor which detects an angular position of the pedal lever and emits a corresponding electrical signal, and with a restoring spring system for restoring the pedal lever to a starting position. A bearing pin can be used to support the pedal lever in a very favorable, precise, and play-free manner on the support structure connected to a vehicle body.
Based on the accelerator pedal disclosed in JP-A-60-99729, the object of the invention is to achieve the fact that the pedal lever is precisely supported and that a friction hysteresis occurs when the pedal lever is actuated, where this friction hysteresis should be achieved with simple means and should be precisely definable and in addition, the friction hysteresis should increase with increasing actuation of the pedal lever.
U.S. Pat. No. 5,408,899 has disclosed a pedal apparatus in which a number of spacers are provided for the purpose of generating friction and the coils of restoring springs are supported on the spacers. A movement of the pedal lever produces relative movements between the spacers and the restoring springs. As a result, friction is produced between the spacers and the bearing pin, among the various spacers, and also between the spacers and the restoring springs. In this very expensive design, it is disadvantageous that the friction depends very heavily on dimensional tolerances of the components and another disadvantage is the friction between the spacers and the restoring springs because this results in the fact that the restoring springs, which represent a safety-related component, fail particularly easily with extended use. Another disadvantage is that the friction is not directly related to the restoring force.
International patent application WO 97/12780 has disclosed an accelerator pedal module in which a semicircle with a relatively large radius is provided on the pedal lever and the support structure has a bearing shell in which the semicircle of the pedal lever is supported. The radius of the semicircle and the bearing shell must be relatively large in order to achieve the desired friction. In this design, it is disadvantageous that the support of the pedal lever and the generation of the desired friction occur directly in the same place. Because the friction surface provided between the semicircle and the bearing shell serves not only to produce the friction force but also to support the pedal lever, very high demands must be placed on the form precision as well as the surface quality and concentricity of the friction surface. In other words, because the support location is used not only to support the pedal lever but also to generate the friction, the structural design must take into account not only support considerations but also frictional considerations. Compromises must therefore be made, as a result of which the entire structure is somewhat unstable and the pedal lever is not supported in a particularly precise manner, which can be detected when the electrical signal is generated at high-resolution. In addition, it is quite expensive to produce the known accelerator pedal module.
German patent application DE 4426549 A1 has disclosed an accelerator pedal module in which the pedal lever is supported in two short shell arcs provided with a friction lining. The shell arcs have a relatively large diameter in order to achieve a sufficient friction. Because of the large diameter of the shell arcs and because the shell arcs are relatively short, it must be concluded that in a pedal lever support of this kind, the support of the pedal lever is quite unstable. As a result, a precise electrical signal can hardly be expected with this accelerator pedal module.
The accelerator pedal module according to the invention has the advantage over the prior art that for a low cost, a precise support of the pedal lever on the support structure can be achieved and a friction force can be achieved that depends on the actuated pivot angle of the pedal lever. A particular advantage is that the generation of the friction force is achieved by simple means. It is particularly advantageous that the pedal lever support and the friction force generation are achieved by mutually independent means. The means for supporting the pedal lever and the means for generating the friction force can each be optimally designed for their respective purposes. As a result, a high degree of precision can be achieved in the support of the pedal lever. The precise support of the pedal lever has the advantage that a precise electrical signal can be produced that indicates the position of the pedal lever.
If two friction surfaces and two friction elements are provided, then this has the advantage that the support of the pedal lever in the vicinity of the support location can be embodied as essentially symmetrical, as a result of which the precision in the support of the pedal lever can be improved even further. In particular, the two friction surfaces and friction elements can be affixed symmetrically with regard to the longitudinal direction of the pedal lever.
The crossbar can be used to connect the two friction elements to each other in a very simple manner and the restoring spring system can act on the crossbar. As a result, the entire design is very simple and a uniform distribution of the force of the restoring spring system onto the two friction elements can be advantageously achieved.
The coupling lever can advantageously transfer the force of the restoring spring system onto the friction element.
If the coupling lever is connected to the support structure in a one-piece, articulating fashion, then this has the advantage that fewer components have to be assembled.
If the coupling lever is connected to the friction element in a one-piece, articulating fashion, then this has the advantage that the friction element and the coupling lever can be produced together and fewer components have to be assembled during assembly of the accelerator pedal module.